How Phoenix Is Getting Ready For 100-Degree Nights

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Written by Ari Phillips

“Phoenix is already hot, and it’s getting hotter,” Mayor of Phoenix Greg Stanton said at a panel held at the Center For American Progress (CAP) today. “We’ve had more extreme heat and longer periods of heat — each year it seems like we get a report that it was the hottest summer on record.”

Stanton speaks the truth. The city averages more than 100 days a year with temperatures reaching over 100 degrees. In 2013, 115 days hit 100 degrees. In 2011, the city set a new record for days over 110 degrees with 33. That’s over one month of the year with scorching highs. This winter has so far been warmer than average.

Stanton said that climate change is happening now and it’s real. While he sounded convincing in his assessment that Phoenix is ready to confront the challenges it poses, he may have downplayed the magnitude of the task, even in saying it will “have a huge impact on how we plan for the future of the city.”

Take water for instance. Stanton said that Phoenix has done a good job of water planning compared to many other Western cities and that droughts will impact surrounding rural communities more.

The Phoenix metropolitan area’s four-million-plus residents get over a third of their water from the Colorado River, which is currently tasked with providing water to over 40 million people. The river is already in a decade-long drought and studies now show that the 20th century was one of the three wettest of the last 13 centuries in the Colorado basin. Populations throughout the Southwest are forecast to grow, and while Phoenix has other sources of water and Arizona has a 100-year water plan, the combined challenges of climate change, drought and overallocation should put fear into any city planner’s mind.

Part of dealing with Phoenix’s challenges is to make the city look different. “Phoenix has to become more urbanized,” Stanton said. “We’re a sprawled city over 500 square miles, we need to change that. People need to move close to the center.”

Stanton mentioned the urban heat island effect as a “tremendous issue” for the city. He said they have a shade plan for the built environment and also a plan to “frankly just plant more trees.”

What he didnt say was that in the last half century nighttime lows have gone from very rarely remaining above 90 degrees to being commonplace during the summer months.

“It’s been getting significantly hotter,” Harvey Bryan, senior sustainability scientist at ASU’s School of Architecture and Landscape Architecture told Phoenix Magazine. “It’s a magnitude now of about 12 degrees above our historical nighttime lows. It was very typical to have summer evenings of 78 degrees back in the 1950s. Today we rarely go below 90. I think we’re headed to conditions where we have 100 degrees as our maximum nighttime low.”

The extreme heat and the heat island effect have also led Stanton to change the way the city looks at human services planning, and to make sure that on the hottest days those in need are taken off the street and into air-conditioned areas “because it can be deadly.” That’s assuming air-conditioning is readily available.

“Heat, however, is a tricky adversary,” writes William DeBuys, author of the book A Great Aridness about the future of the Southwest.

“It stresses everything, including electrical equipment. Transformers, when they get too hot, can fail. Likewise, thermoelectric generating stations, whether fired by coal, gas, or neutrons, become less efficient as the mercury soars. And the great hydroelectric dams of the Colorado River, including Glen Canyon, which serves greater Phoenix, won’t be able to supply the “peaking power” they do now if the reservoirs behind them are fatally shrunken by drought, as multiple studies forecast they will be.”

This week mayors from across the country are gathering in Washington, D.C. for the U.S. Conference of Mayors. Phoenix, with its desert location and large population, is in an especially precarious position. But all cities are struggling with the impacts of climate change in their own way.

Mayor of San Francisco Edwin M. Lee, also in attendance at the CAP panel, took a broader perspective.

“One of the main things I’m doing at this conference is talking about things like water and wastewater infrastructure as a way forward for partnerships between cities and the federal government,” he said. “We’re kind of getting unprecedented engagement with the President this year. He’s signaled that he wants to work directly with mayors. I can understand that when you’re banging your head with Congress and you come to the mayors and they say ‘yes we can do that.’”

San Francisco has been implementing green building standards, investing in sustainable forms of transportation, building major wastewater infrastructure and working hard to reclaim beaches that are eroding due to extreme weather and rising sea levels.

Keeping up with climate change is an expensive endeavor. California is experiencing one of the worst dry spells in its history. Last week Governor Jerry Brown declared the state officially in drought during a trip to San Francisco, asking all Californians for a voluntary “20 percent conservation of our water use.”

According to Lee, San Francisco was able to invest nearly $10 billion over the last decade reinforcing water infrastructure, which he said made the city “very fortunate.” Not all urban areas will be able to place such large downpayments on investing in climate resiliency.

“Infrastructure is very important,” Lee said. “It takes some investment, but once you do it, it’s easy. Then you’re thinking the right way. You can’t just move the hose over, you actually have to create the infrastructure to sustain the system.”

Over the long-term these investments will more than pay off. A CAP analysis about the biggest growing threats to American cities says that “investments in community resilience save lives and taxpayer dollars”:

A study for the Federal Emergency Management Agency, or FEMA, estimated that every $1 invested in community resilience will reduce disaster damages by $4. What’s more, a groundbreaking CAP study from June found that in FY 2011–2013, federal taxpayers spent $6 on disaster cleanup for every $1 spent on community resilience.

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83 comments

I lived in the Phoenix metroplex, and you still see them constructing housing the standard way, instead of following the First People's model of extra-thick adobe walls, with no windows facing south and natural ventilation windows and openings. You're going to read more and more about brown outs and heatstrokes in the area if things don't change there.